Here's a surprise for you
5. This is not quite right. Special rules do apply to protecting the CIK that switches the STU-III to secure mode, but the CIK does not always need to be locked in a safe.
The abbreviation STU-III stands for Secure Telephone Unit -- third generation. The telephone instrument itself is not classified. It may be installed and used in any room in which classified conversations are permitted. To understand why a lower level of protection is permitted and learn about some special circumstances when the key requires a higher level of protection, see Using the STU-III.
Related Topic: Intercepting Your Communications.